Let us say that an Euclidean polyhedral manifold is a manifold that is glued from a finite number of Euclidean polyhedrons by identifying isometrically their co-dimension $1$ faces. Let us assume that no two faces of one polyhedron are glued together and that any two polyhedrons share at most one face.
Let us say that a topological polyhedral manifold is the same thing but this time the faces are identified only by a diffeomorphism, and not necessarily by an isometry. Nevertheless we require that the result of gluing is a manifold.
Question. Suppose now we have a topological polyhedral three manifold. Is it always possible to choose an Euclidean structure on each of its three-dimensional faces (making these faces Euclidean polyhedrons), so that the manifold becomes a Euclidean polyhedral manifold?
Obvious remark. The answer is yes in case of surfaces, one can just say that the surface is glued from regular polygons.